Custom loot tables not working on on mannequin entities

I want to have the new mannequin entity to drop certain items from a loot table on my datapack, but when I summon the mannequin with the custom DeathLootTable set to the one in my datapack, the entity doesn't drop anything when killed. I've tested the loot table with a pig, and did drop as normal, so I think only mannequins are unable to drop items from a custom loot table. I've also tried summoning mannequins leashed so a post, but it did not work as well. Is there a way to modify the mannequin entity to be able to be leashed and have custom loot tables via my datapack?